My Math Forum Need help with a math problem.

 Algebra Pre-Algebra and Basic Algebra Math Forum

 September 14th, 2017, 11:44 PM #1 Newbie   Joined: Sep 2017 From: Oregon Posts: 1 Thanks: 0 Need help with a math problem. In math class this problem plz explain how to solve and what work you did. X=-9 x^2+3 X^2 is my way of saying x is squared.
 September 14th, 2017, 11:58 PM #2 Senior Member   Joined: May 2016 From: USA Posts: 1,245 Thanks: 515 Is the problem $x = -\ 9 + x^2 + 3$ or $x = -\ 9x^2 + 3$? There are FOUR methods to solve quadratic equations. Which ones have you been taught so far? It is hard to help when you tell us nothing about what you have tried or even thought about.
 September 15th, 2017, 05:34 AM #3 Math Team   Joined: Jan 2015 From: Alabama Posts: 3,261 Thanks: 895 The simplest thing to do is to use the "quadratic formula". Given a general quadratic equation, $\displaystyle ax^2+ bx+ c= 0$, you can apply "completing the square" to it to get $\displaystyle x= \frac{-b\pm\sqrt{b^2- 4ac}}{2a}$. Here 9x^2+ x= 3 is the same as 9x^2+ x- 3= 0 so a= 9, b= 1, and c= -3. So $\displaystyle x= \frac{-1\pm\sqrt{(-1)^2- 4(9)(-3)}}{2(9)}= \frac{-1\pm\sqrt{109}}{18}$.
September 15th, 2017, 06:06 AM   #4
Math Team

Joined: Oct 2011

Posts: 13,780
Thanks: 970

Quote:
 Originally Posted by JeffM1 Is the problem $x = -\ 9 + x^2 + 3$ or $x = -\ 9x^2 + 3$?
Probably x = - 9 + x^2 + 3 : has simple integer solution...

 September 18th, 2017, 01:39 AM #5 Newbie   Joined: Sep 2017 From: Bathinda Posts: 2 Thanks: 0 Math Focus: Algebra For this particular solution x = − 9 + x² + 3 or x = − 9x² + 3 x = −b ± √(b² − 4ac) $\ \ \ \ \$ −−−−−−−−−−−−− $\ \ \ \ \$ $\ \ \ \$ $\ \ \ \$ 2a Last edited by skipjack; April 28th, 2018 at 01:23 AM.

 Tags math, problem

 Thread Tools Display Modes Linear Mode

 Similar Threads Thread Thread Starter Forum Replies Last Post tongass Elementary Math 6 December 6th, 2016 04:07 AM ariorakip Elementary Math 4 November 1st, 2015 11:27 AM mathstudent Algebra 2 April 17th, 2010 11:37 AM caitz Algebra 2 September 23rd, 2009 11:30 PM codename211 Math Events 11 August 8th, 2007 08:30 PM

 Contact - Home - Forums - Cryptocurrency Forum - Top